A patient may need respiratory assistance as a result of disease and/or injuries of various kinds. This need for respiratory assistance can be direct, especially when the injury or illness afflicts the patient's respiratory system. In one example, patients in acute respiratory failure may need respiratory assistance. The need for respiratory assistance can also be indirect, for example as during anesthesia. Typically, the extent of respiratory assistance may encompass a range from facilitating spontaneous breathing to total control of breathing.
A mechanical ventilator that moves gas into the lungs of a patient using positive pressure to move air into the lungs may be used to provide respiratory assistance. Although this respiratory assistance may be life saving, long-term use of a mechanical ventilator may not be ideal. For example, long-term mechanical ventilation use may result in weakening of the diaphragm of the patient because of disuse, and use of positive intrathoracic pressures may cause barotrauma, as well as provide inadequate ventilation of the posterior lobes of the lung, thereby possibly contributing to atelectasis, and generally compromising hemodynamics of the patient, which can have further deleterious consequences.